Jet spray nozzle

ABSTRACT

The object of the invention is to provide a thin, close curtain of liquid, for instance in fire-fighting. According to the invention, this is achieved by use of a nozzle having a central control body which is movable within an outer sleeve, both the control body and the outer sleeve having gently tapering wall portions facing each other. The gently tapering portion of the control body merges smoothly into the rear side of a disc-shaped end portion provided thereon, such that the liquid, in a thin layer, will follow the central control body and be deflected into a substantially radial direction relative to the nozzle so as to form a liquid curtain directed transversely in relation to the nozzle.

The present invention relates to a jet spray nozzle, preferably forfire-fighting, which is adjustable between a position for producing aconcentrated jet and a position for producing a scattered jet, by axialdisplacement of a central control body in relation to an outer sleevesurrounding the central control body which, counting in the direction offlow, has a narrow neck portion merging into a disc-shaped end portion.

The primary object of the invention is to provide a jet spray nozzle ofthe above-mentioned type which makes it possible, in an efficient mannerand with a minimum of flow losses, to produce a thin-layer, yet closecurtain of liquid efficiently spread in the transverse direction of thenozzle. In fire-fighting, it may prove highly essential to be able toproduce such a water curtain, for instance when the firemen should enterpremises which are overheated and/or filled with smoke. The liquidcurtain may then be used as a protective shield.

According to the invention, this object is achieved by a jet spraynozzle substantially characterised in that the central control body hasa portion gently tapering, preferably conically, in the direction offlow and smoothly merging into the rear side of said disc-shaped endportion, said outer sleeve having a similarly gently tapering internalportion and terminating at some distance behind the rear side of thedisc-shaped end portion when said control body is in a position ofdisplacement in which a narrow annular passage is formed between saidgently tapering portions of the control body and of the outer sleeve,such that liquid flowing through the nozzle will follow the gentlytapering portion of the control body in a thin layer and at a highvelocity and be gently deflected outwards into a radial direction whilestill flowing in a thin layer along the rear side of the disc-shaped endportion of the control body so as to form an extended curtain in frontof the jet spray nozzle.

Suitably, the gently tapering portion of the outer sleeve narrows intoan inner diameter which is smaller than or equal to the outer diameterof the control body at the point where the gently tapering portionthereof starts, such that the nozzle can be shut off by moving thecontrol body forwards into engagement with the tapering portion of theouter sleeve.

Preferably, the outer sleeve further has a cylindrical mouth portioninto which the disc-shaped end portion of the control body can beretracted for producing a concentrated jet.

An embodiment of the invention will be described hereinbelow withreference to the accompanying drawings, in which:

FIG. 1 is a longitudinal section schematically showing a jet spraynozzle according to the invention in shut-off position,

FIG. 2 is a similar longitudinal section of the same jet spray nozzleadjusted for producing a concentrated, forwardly directed jet, and

FIG. 3 is a perspective view partly in longitudinal section of the samenozzle adjusted for producing a jet shield efficiently spread in thetransverse direction of the nozzle.

The jet spray nozzle shown in the drawings consists of an inner controlbody 1 in the form of a sleeve which is closed at the mouth end of thenozzle and the inner cavity 2 of which, adjacent the closed sleeve endportion 3, communicates with the space surrounding the control body,through a number of bores 4 radially distributed along the circumferenceof the control body. After the bores 4, counting in the direction offlow, i.e. to the right in the drawings, the cylindrical portion 5 ofthe control body passes in a gently, preferably conically taperingportion 6 which, through a smoothly rounded portion 7, merges into therear side 8 of a disc-shaped end portion 9 of the central controlbody 1. The control body is displaceably guided in an outer sleeve 10which surrounds the control body and in relation to which the centralcontrol body is sealed by means of a number of 0-rings 11 mounted ingrooves in the central control body. Outside the outlet openings of theradial bores 4, the outer sleeve has an internal recess 12 which,counting in the direction of flow, merges into a gently, preferablyconically tapering portion 13 whose internal conical surface 14 passes,in the direction of flow, into a diameter which is slightly less thanthe maximum diameter of the concially tapering portion 6 of the centralcontrol body. Downstream of its portion 13, the outer sleeve passes intoan internal cylindrical portion 15 which in the closing position shownin FIG. 1, where the conical portion 6 of the central control bodyengages the portion 13 of the outer sleeve, ends before the rear side 8of the disc-shaped end portion 9 of the central control body. The outersleeve is surrounded by a gripping sleeve 16 which preferably consistsof soft material, such as rubber or plastics, and which suitably, butnot necessarily, has radial wings 17 projecting in the direction offlow. When fluid pressure prevails in the interior of the centralcontrol body and, hence, also in the annular space 12 in the outersleeve and the central control body 1 is moved to the left in thedrawings, i.e. such that the conical surfaces 6 and 14 are movedslightly away from each other, the liquid flowing past the valve bodythus formed will follow the preferably conical circumferential surfaceof the central body in a thin layer and at a high velocity. This thinlayer of liquid, preferably water, will then be gently deflected againstthe rear side of the disc-shaped end portion 9 of the central controlbody into a radial direction, as appears from FIG. 3. This results in aliquid curtain spread in the transverse direction of the nozzle andefficiently deflected into a thin close shield the closeness of whichincreases by the scattering of the water droplets produced by the wings17 of the gripping sleeve 16 projecting into the liquid shield.

When the inner control body 1 is moved further against the direction offlow into the position shown in FIG. 2, the disc-shaped end portion 9will be retracted into the cylindrical end portion 15 of the outersleeve and the conical surfaces 6 and 14 will be moved further away fromeach other so as to widen the passage therebetween. As a result, theliquid flow lamina producing effect of the conical surfaces ceases, andthe liquid flow will be guided by the cylindrical end portion of theouter sleeve so as to form a well-centered jet.

In the illustrated embodiment, the conical surfaces seal directlyagainst each other. This is appropriate when at least one of the partsconsists of relatively soft material. If both parts consist of hardmaterial, sealing can be effected by means of a supplementary sealingmember provided in either one of the parts.

Since in connection with the displacement of the central control body inthe opening direction in relation to the throttling portion of the outersleeve, the disc-shaped end portion of the control body moves towardsthe free end of the outer sleeve, it is possible by a suitable axiallocation of these portions of the central control body and of the outersleeve, to obtain a constant flow of liquid through the nozzle,substantially independently of the relative positions of displacement ofthe parts.

The invention is not restricted to the embodiment described above by wayof example only and illustrated in the drawings, but may be varied as toits components within the scope of the accompanying claims withoutdeparting from the basic concept of the invention. Thus, for example,the design of the inner control sleeve may be varied, like the design ofthe outer sleeve. The inner sleeve need not necessarily be a homogeneouspiece, as shown in the drawings, but may instead consist of a number ofparts connected to each other, which may for instance be suitable whenit is desirable, for reasons of manufacture or other reasons, to usedifferent materials in the different parts of the sleeve. The annularrecess 12 in the outer sleeve produces an excellent distributing effecton the water flowing through, but this distribution may of course beobtained otherwise, for instance by means of a suitable recess cut inthe central control body. The smooth transition between the taperingportion of the central control body and the rear side of the disc-shapedend portion is not restricted only to the illustrated shape where thesurfaces merge into each other along an arcuate line, but also impliestransitions with small angular changes, although the true arc shapeprovides optimum effect.

I claim:
 1. A jet spray nozzle which is adjustable between a positionfor producing a scattered flow an a position for producing aconcentrated flow by axial displacement of a central control body (1) inrelation to an outer sleeve (10) surrounding the central control body(1) characterized in thatsaid central control body (1) has an inner openflow inlet end and a closed outer flow outlet end (3) formed as a valvehead having:a conical portion (6) gently tapering in the direction offlow and forming; a narrow neck portion (7), and a disk-shaped endportion (9) having an inner face (8) wherein said narrow neck portion(7) smoothly merges with said inner face (8) to form a continuoussurface; said outer sleeve (10) has:a gently tapering internal sleeveportion (13) complimentary to said conical portion (6) wherein saidinternal sleeve portion (13) has an inner diameter of up to an outerdiameter of said control body (1) along said conical portion (6) wherebysaid internal sleeve portion (13) forms a seat upon engagement with saidconical portion (6) when said outer sleeve (10) is moved against thedirection of flow relative to said central control body (1) therebyclosing said nozzle; and a cylindrical end portion (15) into which saiddisk-shaped end portion (9) is retracted when said outer sleeve (10) ismoved in the direction of flow relative to said central control body (1)wherein said inner face (8) of said disk-shaped end portion (9) extendsbeyond said end portion (15) of said outer sleeve (10) when said nozzleis closed, whereby axial displacement of said outer sleeve (10) in thedirection of flow relative to said central body (1) opens said nozzle byforming an annular passage between said sleeve portion (13) and saidconical portion (6) and the flow through the nozzle follows the gentlytapering conical portion (6) of the central control body (1) and isdeflected outwards in a radial direction by the inner face (8) of saiddisk-shaped end portion (9) so as to form a divergent curtain of flow infront of the nozzle without interference from the end portion (15) ofthe outer sleeve (10) and whereby further axial displacement of saidouter sleeve (10) in the direction of flow relative to said centralcontrol body (1) retracts said disk-shaped end portion (9) into saidcylindrical end portion (15) of said outer sleeve (10) therebyincreasingly converging the flow in proportion to the displacement ofthe outer sleeve (10).